Temporal Trends and Predictors in the Use of Aldosterone Antagonists Post-Acute Myocardial Infarction
What are the trends in aldosterone inhibitor (Aldo-I) use in patients with reduced ejection fraction (EF) following acute myocardial infarction (AMI)?
The American Heart Association’s Get With the Guidelines–Coronary Artery Disease national database was queried (2006-2009). Inclusion criteria required patients to have a discharge diagnosis of AMI, a left ventricular (LV) EF <40%, and no obvious contraindications to Aldo-I therapy (i.e., excluded those with creatinine >2.5 mg/dl, potassium >5.0 mEq/L, documented Aldo-I allergy). The main outcome was the frequency of Aldo-I prescriptions at the time of discharge.
There were 11,255 eligible AMI-heart failure patients with a mean age of 66 years and median (interquartile range) LVEF of 30% (25%-35%). Of these patients, 1,023 (9.1%) were prescribed an Aldo-I on discharge. Aldo-I use increased from 6% in 2006 to 13% in 2009. Patients prescribed an Aldo-I were more likely to be African American; have a history of hypertension, lower serum creatinine, and lower LVEF; and were more likely to have had a defibrillator and/or resynchronization therapy in place (all p < 0.05). Characteristics of hospitals that were more likely to prescribe Aldo-I included larger size, Southern location, urban setting, and heart transplant capabilities (all p < 0.05). Aside from beta-blocker therapy (utilized less in Aldo-I hospitals), adherence to use of other evidence-based medication was similar between Aldo-I prescribing and nonprescribing hospitals. Multivariable predictors of Aldo-I use included a prior history of heart failure (odds ratio [95% confidence interval] 1.6 [1.4-1.9]), prior revascularization (1.37 [1.2-1.6]), history of diabetes (1.23 [1.08-1.41]), absence of smoking (0.85 [0.75-0.98]), history of renal dysfunction (0.68 [0.52-0.89]), and lower LVEF (0.54 [0.49-0.60]).
The authors concluded that many patients eligible for Aldo-I in AMI are not receiving them.
Recent studies have demonstrated the benefit of aldosterone inhibition in those with ischemic heart disease. Yet, while utilization of such therapies is improving, few as of 2009 appear to be prescribed the agents upon hospital discharge. Other studies have shown that prescription of evidence-based medications, in general, upon patient discharge leads to better longer-term utilization of evidence-based medication. It is unclear based on this study why clinicians are not prescribing such therapies, but patients who were not discharged on Aldo-I had higher serum creatinines. Safety concerns regarding hyperkalemia exist and are real. However, patients with renal dysfunction are also at greater risk for heart failure mortality, and close monitoring of electrolytes is one means of ensuring Aldo-I safety. It is clearly time to sort out why clinicians are not ‘getting with’ this guideline.
Keywords: Myocardial Infarction, Mineralocorticoid Receptor Antagonists, Heart Failure, Hyperkalemia, Creatinine, Patient Discharge, Hypertension
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